The present invention relates to a method of forming a carbon doped oxide layer on a substrate, e.g., a substrate used to make a semiconductor device.
Semiconductor devices include metal layers that are insulated from each other by dielectric layers. As device features shrink, reducing the distance between the metal layers and between metal lines on each layer, capacitance increases. To address this problem, insulating materials that have a relatively low dielectric constant are being used in place of silicon dioxide (and other materials that have a relatively high dielectric constant) to form the dielectric layer that separates the metal lines.
A material that may be used to form such a low k dielectric layer is carbon doped oxide (xe2x80x9cCDOxe2x80x9d). Using this material instead of silicon dioxide to separate metal lines may yield a device having reduced propagation delay, cross-talk noise and power dissipation. A conventional process for forming a CDO layer yields a material that has a dielectric constant of about 3.0. In some circumstances, it may be desirable to further reduce the dielectric constant for that layer.
Accordingly, there is a need for an improved process for making a carbon doped oxide insulating layer. There is a need for such a process that generates a CDO material with a reduced dielectric constant, which can be easily integrated into existing processes for making semiconductors. The method of the present invention provides such a process.